"A university professor was killed today in Texas after a three month experiment ended abruptly. He was visiting every state capitol and burning American flags in front of them."

"A university professor was killed today in Boston after a three month experiment ended abruptly. He was visiting every major U.S. city and driving the speed limit in the left lane."

"A university professor was killed today in Harlem after a three month experiment ended abruptly. He was visiting urban slums wearing nothing but a speedo and a sandwich board that read, 'I HATE N*****S'."

"A deranged homeless man was killed today in Coppenhagen. He was posing as a university professor performing three-month experiments, acting like a total douchebag. A group of actual university professors screamed at him that he was giving them all a bad name, and then they killed him."

Actually, email is a content delivery system. It's up to the participants to decide the content. A stamp is perfectly valid content.

"require a specific definition to 'SPAM' that all agree on."

No, each person decides what spam is. I thought that was pretty obvious from what I was saying, sorry.

You do something publicly on the internet, and leave your stamp-required email address. I want to get in touch with you, so I send you an email with a stamp. If you decide, for whatever reason, to keep my stamp, I just have to accept that. The stamp was a nominal charge in the first place. Chances are, someone will send me an email I don't particularly want to receive, and I can keep their stamp to offset your action. Perhaps it will be considered rude to not return stamps. Perhaps it will be considered gracious to INSIST that recipients keep your stamps so they can donate them to their preferred charities, or use them themselves. Would you donate some email stamps to the homeless, so they can be more effective in emailing potential employers, or health care providers, or state representatives?...just a thought.

Physical mail has more impact than email, when you write to your senator. Perhaps stamped email will carry a tad more weight. "Oh, geez - this is a $20 stamp, and it's even marked for-charity-only." (The recipient CAN'T return it, and CAN'T use it themselves...?)

"However, what if someone you haven't talked to in a while just sends an email out of the blue? is that spam? I know someone who considers that spam."

Then people will either not mind buying stamps to email that person, or they will. If that person ever wants to send emails back, the original senders you described should keep their stamp as payback.

"What about things that are not legally considered spam?"

"Legally" has nothing to do with it. It's a reusable stamp. Apply it to any purpose you want to.

"Or, you could get a Google account."

I've already got one, but I'm not quite cavalier enough to post my gmail address all over creation. Are you? Does it really work well enough on your spam?

The credit card charge happens one time - load up your Spam Busting account with $10 worth of credit. Maybe the system even prevents you from ever withdrawing your money (or any money you get from spammers) back from it. If you could get money back, you could make a profit, and then you're into the realm of paying taxes and reporting income to the IRS. Instead, the system lets you donate to one of say a hundred charities, at any time (rolled up into a monthly donation with other people).

"requires everybody to be on your system"

At first it might - but it could easily be a federation of like-minded providers with simple, secure protocols between them.

Also, this is merely an intermediary between your public internet persona and your real email address. All your friends still use your real email address. When someone wants to make the jump from "random person on the internet who wants to send you an email" to "someone you'd give your real email address to," they send you an email with a stamp on it, you read the email, you give them back their stamp and then you just send them your real email address. If you think there's a chance they might turn into a psycho and sell your email address to Nigeria, then never give them your real email address. Yes, if someone or some virus steals one of your friends email address book, you're screwed. So, maybe you just use the Spam Busting account all the time, but you manage your whitelist. Kind of a pain. The only reason it's ANY better than setting up your own email filters is because you A) can have a public web email account and B) you increase the odds that spammers can't reach you without having to donate to charity to do it.:-)

Thanks for the sarcasm. I'll try to not stoop down as I respond to you:

(*) Mailing lists and other legitimate email uses would be affected

No they wouldn't. You can set up a whitelist.

(*) Users of email will not put up with it

If you have my private email account, you use it. I'm offering up an idea of a service that someone can use to mask their email address. If you really want to contact someone, you can send them a no-stamp email, and hope they happen to see it. This is no better and no worse than today. If you want them to see it, you affix a stamp. The receiver could easily let you know what their threshold level is. If you don't want to pay that much, then don't.

(*) Many email users cannot afford to lose business or alienate potential employers

Many email users will not use the idea. Okay. Some will. If you want to be employed by someone, or do business with them, give them your direct email address.

(*) Ideas similar to yours are easy to come up with, yet none have ever been shown practical

If you desire spam-free email, point out the actual problems with my system. If you don't care to point out the actual problems, then don't.

(*) Sending email should be free

Receiving email should be spam-free. Also, sending email is free under my idea, as long as the people who receive it agree that it wasn't spam. Yes, there's a "deposit" which is held, but it should be good for as long as you don't spam people.

(*) Sorry dude, but I don't think it would work.

That's legitimate. I have Skype credit right now for the simple purpose of making phone calls. I have a recurring credit card debit set up from Amazon to pay for my AS3 (JungleDisk) access. I pay my ISP, and I suspect you pay yours, too. I pay per every text I send from my phone; you might pay a monthly fee to have "unlimited" texts. Returning a book from a library after the due date has a nominal fee.

If I want to send "larry (at) somesite (dot) com" an email, but Larry is as sick of getting spam as I am, and if we agree to trade the same reusable stamp with a group of like-minded individuals, would you seriously be completely unwilling to drop $1 onto a website to join the club?

I remember way back when the signal to noise ratio of email was THOUSANDS of times higher than it is now. I'd be willing to drop a $1 deposit to get back into those kinds of numbers.

I register with a pay-to-email site, and give it my actual email address. It gives me my new publicly visible email address. Anyone who wants to can send me an email through this service if they pay me an amount of money that I set. After I receive the email, I can refund the sender. The pay-to-email site takes a 10% cut on all un-refunded emails.